scholarly journals Attenuation of the Diffuse Noxious Inhibitory Controls in Chronic Joint Inflammatory Pain Is Accompanied by Anxiodepressive-Like Behaviors and Impairment of the Descending Noradrenergic Modulation

2020 ◽  
Vol 21 (8) ◽  
pp. 2973
Author(s):  
Raquel Pereira-Silva ◽  
José Tiago Costa-Pereira ◽  
Raquel Alonso ◽  
Paula Serrão ◽  
Isabel Martins ◽  
...  
Keyword(s):  
Rat Model ◽  
Inflammatory Pain ◽  
Adrenergic Receptors ◽  
Basolateral Amygdala ◽  
Anterior Cingulate ◽  
Noradrenergic System ◽  
Diffuse Noxious Inhibitory Controls ◽  
Dopamine Beta Hydroxylase ◽  
Extracellular Signal ◽  
Noradrenergic Modulation

The noradrenergic system is paramount for controlling pain and emotions. We aimed at understanding the descending noradrenergic modulatory mechanisms in joint inflammatory pain and its correlation with the diffuse noxious inhibitory controls (DNICs) and with the onset of anxiodepressive behaviours. In the complete Freund’s adjuvant rat model of Monoarthritis, nociceptive behaviors, DNICs, and anxiodepressive-like behaviors were evaluated. Spinal alpha2-adrenergic receptors (a2-AR), dopamine beta-hydroxylase (DBH), and noradrenaline were quantified concomitantly with a2-AR pharmacologic studies. The phosphorylated extracellular signal–regulated kinases 1 and 2 (pERK1/2) were quantified in the Locus coeruleus (LC), amygdala, and anterior cingulate cortex (ACC). DNIC was attenuated at 42 days of monoarthritis while present on days 7 and 28. On day 42, in contrast to day 28, noradrenaline was reduced and DBH labelling was increased. Moreover, spinal a2-AR were potentiated and no changes in a2-AR levels were observed. Additionally, at 42 days, the activation of ERKs1/2 was increased in the LC, ACC, and basolateral amygdala. This was accompanied by anxiety- and depressive-like behaviors, while at 28 days, only anxiety-like behaviors were observed. The data suggest DNIC is attenuated in prolonged chronic joint inflammatory pain, and this is accompanied by impairment of the descending noradrenergic modulation and anxiodepressive-like behaviors.

scholarly journals Depressive-like States Heighten the Aversion to Painful Stimuli in a Rat Model of Comorbid Chronic Pain and Depression

2012 ◽  
Vol 117 (3) ◽  
pp. 613-625 ◽  
Author(s):  
Lidia Bravo ◽  
Juan Antonio Mico ◽  
Raquel Rey-Brea ◽  
Beatriz Pérez-Nievas ◽  
Juan Carlos Leza ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Anterior Cingulate Cortex ◽  
Rat Model ◽  
Chronic Mild Stress ◽  
Cingulate Cortex ◽  
Anterior Cingulate ◽  
Mild Stress ◽  
Sham Control ◽  
Neuronal Density ◽  
Extracellular Signal

Background Chronic pain and depression are two complex states with sensory/somatic and emotional components, and they may mutually exacerbate one another in conditions of comorbidity, leading to a poorer prognosis. Methods The authors have evaluated the sensory and emotional components in a rat model combining chronic constriction injury (CCI, a model of chronic neuropathic pain) with unpredictable chronic mild stress (CMS, an experimental model of depression). In addition, the phosphorylation/activation of the extracellular signal-regulated kinases 1 and 2 and neuronal density was also evaluated in the anterior cingulate cortex. Four groups were tested: sham-control, sham-CMS, CCI-control, and CCI-CMS. Results CMS selectively heightens aversion to painful experiences in animals subjected to CCI, as measured in the place escape/avoidance test at 20, 25, and 30 min (CCI-CMS (mean±SEM): 75.68±3.32, 66.75±4.70, 77.54±3.60 vs. CCI-control: 44.66±6.07, 43.17±6.92, 52.83±5.92, respectively), in conjunction with an increase in the accumulation of phosphorylation/activation of the extracellular signal-regulated kinases (CCI-CMS: 4.17±0.52 vs. sham-control: 0.96±0.05) and a decrease in neuronal density in the anterior cingulate cortex. In contrast, chronic pain did not exacerbate the characteristic profile of depression (anhedonia and behavioral despair) in rats subjected to CMS. Furthermore, depression enhances the perception of some specific modalities of sensorial pain such as cold allodynia but has no influence on mechanical threshold. Conclusions These findings support the theory that depression leads to emotional dysfunction in the interpretation of pain in patients suffering chronic pain. In addition, combined animal models of pain-depression may provide a valuable tool to study the comorbidity of pain and depression.

scholarly journals Anxiolytic effect of GABAergic neurons in the anterior cingulate cortex in a rat model of chronic inflammatory pain

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fang-bing Shao ◽  
Jun-fan Fang ◽  
Si-si Wang ◽  
Meng-ting Qiu ◽  
Dan-ning Xi ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Anterior Cingulate Cortex ◽  
Rat Model ◽  
Inflammatory Pain ◽  
Pyramidal Neurons ◽  
Cingulate Cortex ◽  
Gabaergic Neurons ◽  
Gabaergic System ◽  
Anterior Cingulate ◽  
Chronic Inflammatory Pain

AbstractChronic pain easily leads to concomitant mood disorders, and the excitability of anterior cingulate cortex (ACC) pyramidal neurons (PNs) is involved in chronic pain-related anxiety. However, the mechanism by which PNs regulate pain-related anxiety is still unknown. The GABAergic system plays an important role in modulating neuronal activity. In this paper, we aimed to study how the GABAergic system participates in regulating the excitability of ACC PNs, consequently affecting chronic inflammatory pain-related anxiety. A rat model of CFA-induced chronic inflammatory pain displayed anxiety-like behaviors, increased the excitability of ACC PNs, and reduced inhibitory presynaptic transmission; however, the number of GAD65/67 was not altered. Interestingly, intra-ACC injection of the GABAAR agonist muscimol relieved anxiety-like behaviors but had no effect on chronic inflammatory pain. Intra-ACC injection of the GABAAR antagonist picrotoxin induced anxiety-like behaviors but had no effect on pain in normal rats. Notably, chemogenetic activation of GABAergic neurons in the ACC alleviated chronic inflammatory pain and pain-induced anxiety-like behaviors, enhanced inhibitory presynaptic transmission, and reduced the excitability of ACC PNs. Chemogenetic inhibition of GABAergic neurons in the ACC led to pain-induced anxiety-like behaviors, reduced inhibitory presynaptic transmission, and enhanced the excitability of ACC PNs but had no effect on pain in normal rats. We demonstrate that the GABAergic system mediates a reduction in inhibitory presynaptic transmission in the ACC, which leads to enhanced excitability of pyramidal neurons in the ACC and is associated with chronic inflammatory pain-related anxiety.

scholarly journals Strong Manual Acupuncture Stimulation of “Huantiao” (GB 30) Reduces Pain-Induced Anxiety and p-ERK in the Anterior Cingulate Cortex in a Rat Model of Neuropathic Pain

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Xiao-mei Shao ◽  
Zui Shen ◽  
Jing Sun ◽  
Fang Fang ◽  
Jun-fan Fang ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Anterior Cingulate Cortex ◽  
Rat Model ◽  
Cingulate Cortex ◽  
Spinal Nerve ◽  
Anterior Cingulate ◽  
Manual Acupuncture ◽  
Male Adult ◽  
Extracellular Signal ◽  
The Relationship

Persistent neuropathic pain is associated with anxiety. The phosphorylation of extracellular signal-regulated kinase (p-ERK) in the anterior cingulate cortex (ACC) plays an important role in pain-induced anxiety. Acupuncture is widely used for pain and anxiety. However, little is known about which acupuncture technique is optimal on pain-induced anxiety and the relationship between acupuncture effect and p-ERK. The rat model was induced by L5 spinal nerve ligation (SNL). Male adult SD rats were randomly divided into control, SNL, strong manual acupuncture (sMA), mild manual acupuncture (mMA), and electroacupuncture (EA) group. Bilateral “Huantiao” (GB 30) were stimulated by sMA, mMA, and EA, respectively. The pain withdrawal thresholds (PWTs) and anxiety behavior were measured, and p-ERK protein expression and immunoreactivity cells in ACC were detected. PWTs increased significantly in both sMA and EA groups. Meanwhile, anxiety-like behavior was improved significantly in the sMA and mMA groups. Furthermore, the overexpression of p-ERK induced by SNL was downregulated by strong and mild manual acupuncture. Therefore, strong manual acupuncture on bilateral “Huantiao” (GB 30) could be a proper therapy relieving both pain and pain-induced anxiety. The effect of different acupuncture techniques on pain-induced anxiety may arise from the regulation of p-ERK in ACC.

Inhibition of Glutamatergic Synaptic Input to Spinal Lamina IIo Neurons by Presynaptic α2-Adrenergic Receptors

2002 ◽  
Vol 87 (4) ◽  
pp. 1938-1947 ◽  
Author(s):  
Yu-Zhen Pan ◽  
De-Pei Li ◽  
Hui-Lin Pan
Keyword(s):  
Receptor Antagonist ◽  
Synaptic Input ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Dorsal Root ◽  
Primary Afferents ◽  
Noradrenergic System ◽  
Analgesic Action ◽  
Adrenergic Agonists ◽  
Excitatory Synaptic Input

Activation of spinal α2-adrenergic receptors by the descending noradrenergic system and α2-adrenergic agonists produces analgesia. However, the sites and mechanisms of the analgesic action of spinally administered α2-adrenergic receptor agonists such as clonidine are not fully known. The dorsal horn neurons in the outer zone of lamina II (lamina IIo) are important for processing nociceptive information from C-fiber primary afferents. In the present study, we tested a hypothesis that activation of presynaptic α2-adrenergic receptors by clonidine inhibits the excitatory synaptic input to lamina IIo neurons. Whole cell voltage-clamp recordings were performed on visualized lamina IIo neurons in the spinal cord slice of rats. The miniature excitatory postsynaptic currents (mEPSCs) were recorded in the presence of tetrodotoxin, bicuculline, and strychnine. The evoked EPSCs were obtained by electrical stimulation of the dorsal root entry zone or the attached dorsal root. Both mEPSCs and evoked EPSCs were abolished by application of 6-cyano-7-nitroquinoxaline-2,3-dione. Clonidine (10 μM) significantly decreased the frequency of mEPSCs from 5.8 ± 0.9 to 2.7 ± 0.6 Hz (means ± SE) without altering the amplitude and the decay time constant of mEPSCs in 25 of 27 lamina IIo neurons. Yohimbine (2 μM, an α2-adrenergic receptor antagonist), but not prazosin (2 μM, an α1-adrenergic receptor antagonist), blocked the inhibitory effect of clonidine on the mEPSCs. Clonidine (1–20 μM, n = 8) also significantly attenuated the peak amplitude of evoked EPSCs in a concentration-dependent manner. The effect of clonidine on evoked EPSCs was abolished in the presence of yohimbine ( n = 5). These data suggest that clonidine inhibits the excitatory synaptic input to lamina IIo neurons through activation of α2-adrenergic receptors located on the glutamatergic afferent terminals. Presynaptic inhibition of glutamate release from primary afferents onto lamina IIoneurons likely plays an important role in the analgesic action produced by activation of the descending noradrenergic system and α2-adrenergic agonists.

Antinociceptive effect of intrathecal P7C3 via GABA in a rat model of inflammatory pain

2021 ◽  
Vol 899 ◽  
pp. 174029
Author(s):  
Sang Wan Ryu ◽  
Yeo Ok Kim ◽  
Han-Byul Kim ◽  
Seog Bae Oh ◽  
Jeong Il Choi ◽  
...  
Keyword(s):  
Rat Model ◽  
Inflammatory Pain ◽  
Antinociceptive Effect

scholarly journals Nav1.7 via Promotion of ERK in the Trigeminal Ganglion Plays an Important Role in the Induction of Pulpitis Inflammatory Pain

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Shukai Sun ◽  
Jiangxing Sun ◽  
Wenkai Jiang ◽  
Wei Wang ◽  
Longxing Ni
Keyword(s):  
Trigeminal Ganglion ◽  
Inflammatory Pain ◽  
Pain Threshold ◽  
Expression Levels ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Pulp Exposure ◽  
Mechanical Pain Threshold ◽  
Hematoxylin Eosin ◽  
Inhibitor Dose

The trigeminal ganglion (TG) refers to sensory neurons bodies that innervate the spinal cord and peripheral axons that innervate teeth. The tetrodotoxin-sensitive sodium (NA) channels (Nav1.7) play important roles in the pathophysiology of pain. In this study, we investigated the TG expression of Nav1.7 and extracellular signal-regulated kinase (ERK) in a rat model of pulpitis to explore the correlation between these channels and inflammatory pain. Pulpitis was confirmed by hematoxylin-eosin staining. In this study, we demonstrated that the reflex of rats to mechanical stimulation increases after pulp exposure and that the exposed rat molar pulp can upregulate the expression of Nav1.7 and ERK in the rat TG. Three days after rat pulp exposure, the expression levels of the two ion channels in the TG increased. TG target injection of PF04856264, a Nav1.7 inhibitor, dose-dependently increased the mechanical pain threshold and was able to inhibit ERK expression. TG target injection of PD98059, an ERK inhibitor, dose-dependently increased the mechanical pain threshold. These factors simultaneously resulted in the highest production. In this study, with the established link to inflammatory pain, we found that Nav1.7 and ERK both play important roles in the induction of inflammatory pain caused by pulpitis. We also found a correlation between the expression levels of Nav1.7 and ERK and the degree of inflammatory pain. Furthermore, ERK signaling pathways were promoted by the Nav1.7 in TG after pulpitis.

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